This disclosure relates to a clearance control arrangement for a gas turbine engine for use in, for example, a compressor section of the engine.
A gas turbine engine typically includes a fan section, a compressor section, a combustor section, a turbine section, in some configurations an augmenter section, and finally a nozzle, or exhaust, section.
It is desirable to maintain tight clearances between rotating blades and adjacent engine static structure. Tight clearances minimize leakage, which improves overall engine efficiency. High temperatures in the engine pose numerous challenges to clearance control, particularly in rotating stages near the combustor section.
Some engines include a compressor section having a low pressure compressor and a high pressure compressor, which is nearer the combustor section than the low pressure compressor. High pressure compressor case arrangements are designed to take into account various materials used within the high pressure compressor and accommodate component stiffnesses. The case supports a rub strip that is designed to seal relative to the rotor blade tips. The case is configured to match compressor rotor and case growth under deflections during engine operation at elevated temperatures. Depending upon the rotor and case material selections, it can be challenging to achieve desired rotor tip clearances relative to the case rub strips or blade outer air seals.
As temperatures in the high pressure compressor increase in advanced engine architectures, the temperature at the aft portion of the compressor section nearest the combustor section makes achieving tight running clearances more difficult. In one fixed stage of the high pressure compressor, a stator cluster is mounted to forward and aft supports. A seal land integral with the aft support has been used to seal with respect to a piston ring supported by an exit guide vane array. A separate cover has been snap fit onto the seal land opposite the piston ring and over the bolted flange.